1. Field of the Invention
This invention pertains to solid fuel, such as coal, agricultural and wood wastes, burners and, more particularly, to improvements in the ash removal and fuel feeding in burners.
2. Description of the Prior Art
The spent consumed ash in wood waste fuel burners has generally been removed by dropping the ash through an opening at a limited number of areas in the combustion chamber. This requires that the ash be removed through a substantial length of travel as it is carried by the sweeper or rabble arms to the vicinity of the ash discharge opening. Since there is always a small amount of residual unburned fuel present with the ash, this lingering of the ash in the vicinity of the underfire air or burning area frequently causes this unburned fuel to reach above stoichiometric temperatures forming slag. The slag is then difficult to remove.
Removal of ash has been a problem in solid fuel burners also due to the fact that the ash could bridge over the discharge openings or its consistency would so vary that it would be difficult to remove by automatic means.
In addition to the difficulties of ash removal, it has long been a difficult problem to feed the unburned fuel to the combustion chamber pile. Since the consistency of wood waste fuel in particular is frequently of greatly varying moisture content, size and frequently carries with it a lot of grit and debris, it tends to pack in the feed delivery tube. This packing results in discharge from the inner end of the delivery tube in a highly compacted cylinder which then, rather than falling uniformly around all 360.degree. of the top of the pile, tends to fall consistently to one side, causing an irregular height to the pile. This irregular shape or height of the pile causes difficulty in controlling combustion, particularly where underfire air is being blown up through the pile. If the pile is not reasonably uniform or symmetrical, the underfire air causes blow holes through the pile, adversely affecting the combustion process.